Method for detecting water meter malfunction, calculating the duration thereof, and device for implementing same

ABSTRACT

A method for detecting water meter malfunction and calculating the duration thereof, includes measuring the average flow rate for each volume unit detected after the preceding volume unit, comparing this average flow rate with two limit flow rates which are a first flow rate corresponding to the minimal flow rate when the meter is operating normally and a second flow rate corresponding to the minimal flow rate when the meter is operating defectively, calculating, when an average flow rate is found to be higher than the first flow rate, the relation between the sum of recorded volume units between the two flow rates and the sum to which is added the sum of volume units recorded at flow rates higher than the second flow rate, starting a clock when this relation is lower than a defectiveness threshold and stopping it when the relation is once more higher than the said threshold.

BACKGROUND OF THE INVENTION

The invention relates to a process for the detection and evaluation ofthe duration of a malfunction of a meter, particularly when said meteroperates in the form of a so-called submarine meter.

DESCRIPTION OF THE RELATED ART

It has been noted that in the course of the use of a water meter, theprecision of the latter can decline because of wear even of the meter orfrom the deposit of solid particles such as sand, in particular duringwork on the pipes.

Most of the time, this decline is manifested in the incapability of thewater meter to measure low flow rates and also gives rise to erroneousmeasurements of higher flow rates. This decline being difficult todetect, there results an erroneous measurement of water consumption.Moreover, the simple detection of the malfunction of a meter does notpermit evaluating the duration of said malfunction and as a result toestimate the erroneous measurement of consumption.

Moreover, when the malfunction of the water meter is due to the depositof solid particles, for example following work, said deposit can benaturally eliminated. Thus, the flow of water flowing through the meterwill gradually entrain the solid particles, restoring the meter to itsnormal condition. Because of this, this type of malfunction can passentirely undetected, the meter having lost and regained its normaloperating characteristics without this having been detected.

This type of malfunctioning meter is called a submarine meter to theextent that its malfunction is practically undetectable and theindications given are less than those that are normal.

It is therefore desirable to overcome these draw-backs by providing aprocess for the detection of the malfunction of a water meter alsopermitting evaluation of the time during which said meter has operatedas a submarine meter.

BRIEF DESCRIPTION OF THE DRAWING

The single drawing FIGURE illustrates the invention.

SUMMARY OF THE INVENTION

To this end, the invention provides a process for the detection of themalfunction of a water meter and for evaluation of the duration of saidmalfunction, characterized in that it comprises: measuring the mean flowrate at each unit of volume detected following the preceding unit ofvolume, comparatively analyzing this mean flow rate at two limit flowrates which are a first flow rate corresponding to the minimum normaloperating flow rate of the meter and a second flow rate corresponding tothe minimum operating flow rate of the meter when the meter isfunctioning in a submarine mode, the computing, when a mean flow rate isdetected greater than the first flow rate, of the ratio between the sumof the units of volumes counted between the first and the second flowrates and this said sum to which is added the sum of the units ofvolumes counted at flow rates higher than the second flow rate, startinga clock when this ratio is below a threshold of submarine operation andstopping said clock when the ratio is again greater than the submarinethreshold.

When the mean flow rate calculated is detected to be below the minimumflow rate of normal operation of the meter, said mean flow rate is nottaken into account because it does not reflect any significant event.

When the calculated mean flow rate is detected to be higher than theminimum flow rate of normal operation of the meter, there is thenperformed an analysis of detection of said operation of a meteroperating in a submarine mode.

Thus, there are separately added the units of volume counted between theminimum normal operating flow rate of the meter and the minimumoperating flow rate of the meter when the meter is in a submarine mode,and the units of volume counted at flow rates higher than the minimumflow rate of the meter when the meter is operating in a submarine mode.

There can thus be calculated the value of the ratio between the volumescounted between the two flow rates and the sum of the volumes countedbetween the two flow rates and the volumes counted above the minimumoperating flow rate of the meter when operating in a submarine mode.

The obtained value is then compared to a value of this ratio below whichthe meter operates in the submarine mode.

When a value of this ratio is detected such that the meter functions ina submarine mode, a clock is started and when the value of the ratio isdetected such that the detector operates normally, the clock is stopped.

There is thus detected not only the malfunction of the meter operatingin a submarine mode but also in a precise manner the duration of thismalfunction.

So as to preserve high sensitivity of the analysis carried out, only themost recent units of volume are processed by a so-called "slidingwindow" technique.

The invention also relates to a device 10 for detecting malfunction of awater meter 20 operating in a submarine mode and for evaluation of theduration of said malfunction according to the process of the invention,characterized in that it comprises means for measuring flow rates 30 inthe water meter 20, means to measure a first volume of water 40 at aflow rate comprised between a minimum normal operating flow rate of themeter 20 and a minimum flow rate of the meter 20 operating in asubmarine mode, and a second volume of water at a flow rate higher thansaid second flow rate and means 50 for starting and stopping a clock 60.

Preferably, the means for measuring the flow rates 30 in the water meterare constituted by means for measuring units of volume 40 passingthrough the water meter constituted by a first electric impulse emitter70 disposed in the meter and delivering an impulse upon each volumeflowing.

The computing means 73 and analysis means 76 are constituted by anelectronic computer 80.

This electronic computer can comprise a display screen 90 on which aredisplayed the results of the measurements carried out. The computer canalso be connected to a data bank permitting computerized retrieval ofthe results.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention will now be described in greater detail with the help ofan example of embodiment in which there is used an emitter of electricalimpulses to input the electronic computer.

A flow rate is defined by the time separating two consecutive impulses.Thus, the minimum normal operating flow rate of the computer D1 and theminimum operating flow rate of the computer D2 when operating in asubmarine mode, are defined by two variables T1 and T2 defining a numberof periods of 4 seconds.

The electronic computer, as a function of the data received from theelectrical impulses of the emitter, deter mines the values of the firstvolume V1 that has flowed at a flow rate comprised between D1 and D2 andof the second volume V2 at a flow rate greater than D2.

A threshold of submarine mode is obtained by the value of the followingratio:

    V1/(V1+V2)=k/256

As to the processing of the "sliding window", there will then bededucted a quantity k from the volume V1 and a quantity 256-k from thevolume V2, when (V1+V2)>VL

Thus, a meter will be operating in submarine mode if:

    256*V1-k*(V1+V2)<0

In these computational formulae, k is a quantity permitting defining apercentage and VL corresponds to the limit volume in liters.

All these values are reprogrammable. The modification of theseparameters involves necessarily a restarting of V1 and V2 from zero,however VL must be able to be modified without resetting V1 and V2 tozero.

Upon each new electrical impulse from the electrical impulse emitter, itis thus necessary to update V1 and V2 to verify that the meter is notoperating in a submarine mode. In the case in which the meter isdetermined to be operating in a submarine mode, the clock is started soas to count the duration of operation of the meter in a submarine mode.When the meter is no longer detected to be operating in a submarinemode, the clock is stopped and it has thus been possible to determinethe length of time of malfunction of the meter operating in a submarinemode.

What is claimed is:
 1. Process for the detection of malfunction of awater meter and for evaluation of the duration of said malfunction,comprising the steps of:measuring the mean flow rate of each unit ofvolume detected following the preceding unit of volume, comparativelyanalyzing this mean flow rate at two limit flow rates which are a firstflow rate corresponding to minimum normal operating flow rate of themeter and a second flow rate corresponding to the minimum operating flowrate of the meter when the meter is operating in a submarine mode,computing, when a mean flow rate is detected higher than the first flowrate, the ratio between the sum of the units of volume (V1) countedbetween the first and the second flow rates and this said sum to whichis added the sum of the units of volume (V2) counted at flow rateshigher than the second flow rate, starting a clock when this ratio isbelow a threshold of submarine operation and stopping said clock whenthe ratio is again higher than this threshold of submarine operation. 2.Process according to claim 1,characterized in that the measurement ofthe mean flow rate detecting a value of the flow rate below said firstflow rate reflects the absence of an event.
 3. Device for the detectionof malfunction of a water meter operating in a submarine mode and theevaluation of the duration of said malfunction according to the processof claim 1,comprising means for measuring units of volume passingthrough the water meter, means for computing a mean flow rate, means forcomparing the flow rate measured by said measuring means with a minimumnormal operating flow rate of the meter and a minimum operating flowrate of the meter operating in a submarine mode, means for computing,when a mean flow rate is detected higher than the minimum normaloperating flow rate of the meter, the ratio between the sum of the unitsof volume (V1) counted between the first and second flow rates and thissum to which is added the sum of the units of volume (V2) counted atflow rates higher than the second flow rate, means for comparing saidratio to a threshold of submarine operation and means for stopping andstarting a clock as a function of the performed comparison.
 4. Deviceaccording to claim 3,characterized in that the means for measuring theunits of volume passing through the water meter are constituted by anemitter of electrical impulses disposed on the meter.
 5. Deviceaccording to of claim 3,characterized in that the computing and analysismeans are constituted by an electronic computer.
 6. Device according toclaim 5,characterized in that said electronic computer comprises ascreen on which are displayed the results of the measurements carriedout.
 7. Device according to claim 5,characterized in that the computeris connected to a data bank permitting computerized retrieval of theresults.